从 Hystrix 获取异常

Posted 2023-03-16

【中文标题】从 Hystrix 获取异常

【英文标题】：Getting exception from Hystrix

【发布时间】：2021-01-31 01:20:39

【问题描述】：

我正在将 hystrix 用于 Spring Boot 项目，但出现超时异常。

详情请查看以下控制器代码

@GetMapping("/getData")
@HystrixCommand(fallbackMethod = "getDataFallBack", commandProperties =  @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "60000"), @HystrixProperty(name = "execution.isolation.strategy", value = "SEMAPHORE") )
public ResponseEntity<Object> getData() 



/**
 * Fallback method for getData
 */
public ResponseEntity<Object> getDataFallBack(Throwable e) 
    LOGGER.info("In fallback method", e)

在测试更多调用时，例如在 5 分钟内点击 1500 次，然后出现超时异常。在检查日志的同时找到下面的日志

java.lang.RuntimeException: could not acquire a semaphore for execution
    at com.netflix.hystrix.AbstractCommand.handleSemaphoreRejectionViaFallback(AbstractCommand.java:966) ~[hystrix-core-1.5.18.jar!/:1.5.18]
    at com.netflix.hystrix.AbstractCommand.applyHystrixSemantics(AbstractCommand.java:554) ~[hystrix-core-1.5.18.jar!/:1.5.18]
    at com.netflix.hystrix.AbstractCommand.access$200(AbstractCommand.java:60) ~[hystrix-core-1.5.18.jar!/:1.5.18]
    at com.netflix.hystrix.AbstractCommand$4.call(AbstractCommand.java:419) ~[hystrix-core-1.5.18.jar!/:1.5.18]
    at com.netflix.hystrix.AbstractCommand$4.call(AbstractCommand.java:413) ~[hystrix-core-1.5.18.jar!/:1.5.18]
    at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.Observable.unsafeSubscribe(Observable.java:10327) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:48) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.internal.operators.OnSubscribeMap.call(OnSubscribeMap.java:33) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.Observable.unsafeSubscribe(Observable.java:10327) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) [rxjava-1.3.8.jar!/:1.3.8]
    at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) [rxjava-1.3.8.jar!/:1.3.8]

谁能告诉我如何解决这个问题？

【参考方案1】：

您需要添加 hystrix 属性execution.isolation.semaphore.maxConcurrentRequests 并将其设置为更高的数字（200）。 execution.isolation.semaphore.maxConcurrentRequests 的默认值为“10”，因此方法 getData() 将被允许并行执行不超过 10 次。

同样，您需要添加 fallback.isolation.semaphore.maxConcurrentRequests 并将其设置为 200 作为您的回退方法。

    @GetMapping("/getData")
    @HystrixCommand(fallbackMethod = "getDataFallBack", commandProperties =  @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "60000"), 
    @HystrixProperty(name = "execution.isolation.strategy", value = "SEMAPHORE"),@HystrixProperty(name = "execution.isolation.semaphore.maxConcurrentRequests", value = "200") )
    public ResponseEntity<Object> getData()